Electric switch



Nov. 10, 1953 Filed Feb. 6. 1950 w. G. BOURNE 2,658,962

ELECTRIC SWITCH 4 Sheets-Sheet l W. G. BOURNE Nov. 10, 1953 ELECTRIC SWITCH 4 Sheets-Sheet 2 Filed Feb. 6, 1950 W. G. BOURNE ELECTRIC SWITCH Nov. 10, 1953 4 Sheets-Sheet 5 Filed Feb. 6, 1950 W. G. BOURNE ELECTRIC SWITCH Nov. 10, 1953 4 Sheets-Sheet 4 Filed Feb. 6, 1950 Patented Nov. 10, 1953 U NI TED S TATE-S PATENT O-F'FIC E ELECTRIC SIVITCH WilIiam GeorgeBourne, Acton, London, England,

assignorto Rot-ax LimitedLondon, England Appllcatloniiebruary :6, 1950, Serial -N 0. 142 661 Claimspriofity, application Great Britain February 7, 1949 For starting internal combustion engines, there is sometimes employed a turbine driven by gases derived from the --'explosion of acartridge, twoor more cartridges being provided for firing in succession in "the event of a fired cartridge failing to effect the required engine starting action.

For controlling the sequence of events in the starting operation an electrically actuated timing mechanism is employed, this mechanism being under the control of "a manually operable switch.

l he object of the present invention is to provide an improved switch for use with an engine starting system of the kind above indicated.

In the accompanying sheets of explanatory drawings:

Figure 1 is a sectional side view of a switch constructed in accordance with the invention for the purpose indicated above.

Figured is a view of the right handend of the switch shown in Figure 1.

Figure 3 is a sectional end view taken on the line 3-3 of Figure 1, the latter being taken on the line l! of Figure 3.

Figure i is a fragmentary sectional side view taken on the line d-fi of Figure -2.

In carrying the invention into effect-as shown, I employ a manually slidable spindle a which is loaded by a spring b, and which is provided at one end with an actuating knob c. The spindle a is adapted at its opposite end to effect the closing of contact pieces e in a circuit which controls the timing mechanism, the contacts cl being fixed, and the contacts e being resiliently supported on the spindle by a spring f. At a position adjacent to the knob '0 there is rotatably mounted around the spindle a a sleeve g which is supported in a fixed tubular member 1/ and. which contains the spindle-loading spring b, the latter being arranged between a shoulder in the sleeve and the inner end-of the knob 0. Secured to the outer end of the sleeve 9 is a hollow actuating knob h which surrounds the knob c on the spindle a. On the member y is freely mounted a rotatable switch member 1 having a peripheral contact piece or pieces adapted to co-operate with. resiliently supported stationary contact pieces k for selecting the firing circuits associated with the different cartridges.

At the inner end of the switch member i is arranged a solenoid having a slidable and rotatable hollow core m mounted on the spindle a and surrounded by the solenoid winding n. On the end. of the core m adjacent to the sleeve 9 is formed or secured a disc 0 carrying locking bolts 12 which extend from the side of the disc remote from the core m and are parallel with the axis of the spindle c. The core m is loaded by a spring in the form of a resilient plate q secured to the disc '0 and provided with laterally bent tongue pieces as '1" which bear against the adjacent end of a stationary casings containing the solenoid winding 12.

Secured to the side of the disc 0 from which the locking bolts "p extend is another disc is hav ing a central hollow boss u which is connected to the sleeve g by an annular plate 11 having an inwardly projecting tongue piece 12 passing through a hole in the sleeve and a longitudinal u in the boss, so that rotational movement of the sleeve is accompanied by corresponding movement of the two discs. The annular plate 12 is secured between a split ring so engaging a peripheral groove on the sleeve 9 and the inner end of the :fix'ed tubular member 31 by which the sleeve is supported, the outer end of the tubular member being secured in a central hole in the adjacent end of a housing 10 enclosing the greaterpart of the switch mechanism above described.

locking bolts 10 pass through slots 2 in the rotatable switch member 2', and are adapted at their outer ends to engage grooves or other recesses 3 in the adjacent end of the housing 20 under the action of the spring q, '1' above mentioned. Four such recesses are arranged at degrees apart around the axis of the rotatable switch member '1', and the outer ends of the 1001:- ing bolts 90 can engage either diagonally opposite pair of these recesses To prevent accidental rotational movement of the switch member '2' when the looking bolts 7: are withdrawn from the adjacent pair of recesses 3, the other pair are engaged by detents on a resilient metal disc 5 of annular form, this disc being formed with outwardly extending projections 5 which extend into and are supported by shoulders in slots 3 formed in the adjacent end of the switch member.

Normally the 'outer ends of the locking bolts 11 engage a pair of the recesses 3 in the housing w as above described, and so prevent movement of the rotatable switch member i, by the associated knob it. When the winding n of the solenoid is energised under the control of the timing mechanism, the core m is actuated to retract the looking bolts p, and the attendant can then actuate the knob h to turn the rotatable switch member i through the medium of the locking bolts for selecting the cartridge to be fired, preparatory to actuating the spindle a by pressing on the knob c for closing the contacts d, e and thereby causing the selected cartridge to be fired.

Preferably the outer end of the knob c is covered by a pivotal and spring loaded cover piece I which is carried by the hollow knob h and re quires to be lifted against the action of its loading spring 8 to expose the knob c for actuation.

For enabling the attendant to determine the positions required to be occupied by the rotatable switch member 1' for selecting the firing circuits, an annular disc 9 of transparent or translucent material is mounted in a recess in the inner side of the end of the housing w adjacent to the knob h, and is adapted to be rotated by the switch member i through the agency of bent resilient metal strips In which at one end are secured to the disc and at the other end are situated in the inner ends of the slots in the switch member. Also the disc 9 is provided with markings which indicate the ve rious positions of the switch member i, and which are successively visible through an opening I I in the adjacent end of the housing to during rotation of the disc with the switch member. Moreover, there is mounted in one side of the housing w a lamp l2 having a side opening 13 through which the part of the disc 9 exposed by the opening I! can be illuminated.

By this invention a switch for the purpose specified is provided in a simple and compact form.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An electric switch for the purpose described comprising, in comb nation, a housing. first switch member rotatably mounted within the housing and carrying contact means adapted to co-operate with a plurality of fixed conte ct means in the housing, a manually operable rotatable member located outside the housing coaxial with the first switch member and operatively con nected therewith for rotating the said switch member for selecting a desired firing circuit, spring-loaded locking plunger mee ns mounted for movement parallel with the axis of rotation of the first switch member and extending through openings in said switch member to engage recesses in the housing under spring loading to lock the said switch member against rotation, a second switch member longitudinally slidable coaxially with the rotatable switch member and carrying contact means adapted to co operate with fixed contact means in the housing for controlling a timing mechanism circuit, a manually operable member located in a recess in said manually rotatable member and disposed coaxially therewith for imparting longitudinal displacement to said longitudinally slidable switch member, a solenoid disposed coaxially with respect to the rotatable and slidable switch members, a movable core for said solenoid slidable upon said longitudinally slidable switch member, and an operative connection between said movable core and said locking plunger means for withdrawing the plunger means from looking position when the solenoid is energised under the control of the timing mechanism, whereby operation of the longitudinally slidable switch member after selection of the de- 4 sired circuit causes the rotatable switch member to be locked against rotation to prevent operation thereof until after the selected firing circuit has been closed.

2. An electric switch for the purpose described comprising, in combination, a housing, a first switch member rotatably mounted within the housing and carrying contact means adapted to co-operate with a plurality of fixed contact means in the housing, a manually operable and rotatable hollow knob located outside the housing coaxial with the first switch member and operatively connected therewith for rotating the said switch member for selecting a desired firing circuit, spring-loaded locking plunger means mounted for movement parallel with the axis of rotation of the first switch member and extending through openings in said switch member to engage recesses in the housing under spring loading to lock the said switch member against rotation, a second switch member longitudinally slidable coaxially with the rotatable switch member and carrying contact means adapted to co-operate with fixed contact means in the housing for controlling a timing mechanism circuit, a manually operable press knob located within the hollow of the manually rotatable knob and disposed coaxially therewith, said press knob being connected to the longitudinally slidable switch member for actuating the latter, a solenoid disposed coaxially with respect to the rotatable and slidable switch members, a movable core for said solenoid slidable upon said longitudinally slidable switch member, an operative connection between said movable core and said locking plunger means for withdrawing the plunger means from looking position when the solenoid is energised under the control of the timing mechanism, and spring-loaded detents carried by the rotatable switch member and engageable in recesses in the housing for preventing accidental rotational movement of said switch member when the locking plunger means are withdrawn, whereby operation of the longitudinally slidable switch member after selection of the desired circuit causes the rotatable switch member to be locked against rotation to prevent operation thereof until after the selected firing circuit has been closed.

3. An electric switch according to claim 2 in which the manually rotatable hollow knob is provided with a pivotally mounted and spring-loaded cover which must be lifted to enable the press knob to be operated.

WILLIAM GEORGE BOURNE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 708,096 Tirrill Sept. 2, 1902 734,291 Appleton July 21, 1903 916,476 McLarty Mar. 30, 1909 1,019,467 Hastings et a1. Mar. 5, 1912 1,078,463 Ransom Nov. 11, 1913 1,889,514 Cook Nov. 29, 1932 1,940,928 Wyman Dec. 26, 1933 1,940,930 Wyman Dec. 26, 2,278,840 Douglas Apr. 7, 1942 2,469,274 Rein May 3, 1949 2,569,511 Bickel Oct. 2, 1951 

